Lighting fixture



Feb. 16, 1965 w. 1.. LIPSCOMB LIGHTING FIXTURE 5 Sheets-Sheet 1 Filed March 16, 1962 INVENTOR. WILLIS L. Ll PSCOMB Feb. 16, 1965 w. 1.. LIPSCOMB 3,169,710

LIGHTING FIXTURE Filed March 16, 1962 3 Sheets-Sheet 2 will! INVENTOR. WILLIS L. LIPSCOMB Feb. 16, 1965 w. LIPSCOMB 3,

LIGHTING FIXTURE Filed March 16, 1962 3 Sheets-Sheet 3 I 111 W JLJELI w INVENTOR.

WILLIS L. LIPSCOMB BY mzm United States Patent 3,159,710 LEGHTEJG FIXTURE Willis L. Lipscomb, 2298 Willow, San Diego, Calif. Filed Friar. 16, 1t2, Ser. No. 139,153 4 Claims. (or. 24 3-13) This invention relates to a lighting fixture, and more particularly to one that provides efiicient cooling of the lamp and a desirable shielded zone.

Background It is well known that the eye has a natural tendency to turn toward the bright light. This has two disadvantages. First, the eye is blinded by the bright light, and cannot see well when it is turned away; and second, the viewer must constantly force the eye to look in the desired direction away from the bright light, toward a Workplace or some object under study. These effects require a distinct muscular effort, and tend to be extremely tiring.

it has also been found that large bright lamps tend to be more eificient than a plurality of small ones. This increased efiiciency shows up in a number of ways. One is that more actual candlepower is generated with the same electric power consumption, and another is simplicity of lighting fixtures that requires only a single pair of sockets and minimal wiring.

The increased efficiency has resulted in a tendency toward more bright-lamp fixtures, with resultant increased tendency toward eye fatigue.

Most lighting fixtures have sought to overcome this situation by using translucent panels that transmit only a portion of the impinging light. This approach has ameliorated the problem, but at the cost of reduced efficiency since some of the available light is wasted. Other lighting fixtures have used translucent side panels and an open egg-crate grillwork at the bottom of the fixture. The open bottom provides direct illumination below the fixture, and also provides a limited amount of sidewardly directed light.

Objects and drawings It is therefore the principal object of my invention to provide an improved lighting fixture.

It is another object of my invention to provide an improved lighting fixture that has remarkably high lighting efficiency while providing a suitable degree of shielding.

It is a further object of my invention to provide an improved lighting fixture that makes adequate provision for cooling of the lamp, and minimization of dust problems.

The attainment of these objects and others is realized in the lighting fixture described in the following specification, and illustrated in the accompanying drawings, in which:

FIGURE 1 is a side elevation view of a lighting fixture incorporating my invention;

FIGURE 2 is an enlarged sectional view taken on line 2--2 of FIGURE 1;

FIGURE 3 is a sectional view similar to FIGURE 2, showing an alternative structure;

FIGURE 4 is a sectional view of a further alternative structure;

FIGURE 5 is a sectional view of still another alternative structure;

FIGURE 6 is a sectional view as taken on line 6-6 of FIGURE 2, but showing a modified end portion;

FIGURE 7 is a sectional view similar to FIG. 6, showing an alternative end arrangement; and

FIGURE 8 is an enlarged, fragmentary sectional View of a modified cellular wall configuration.

Brief description of the invention Broadly stated, my invention contemplates the use of angled slats or louvers positioned and angled so that the resultant panel directs light in predetermined direc tions. The angle panels thus formed transmit substantially all of the impinging light, and yet produce a shielded zone from which the eye cannot see the bright light itself. Furthermore, the open cells of the angle panel inherently permit air circulation, which cools the lamp to its desired operating temperature, and also deters the accumulation of dust.

One embodiment involves the use of my angle panel for producing a lighting fixture wherein the light is directed upwards to provide an indirect lighting effect on the ceiling. Another embodiment uses the angle panel to direct light downwardly, as maybe desired when the ceilings are very high. A third embodiment permits the use of my angle panel to distribute light in a complete circle around the lamp, and another embodiment teaches how the fixture itself may have its surface brightness decreased by judicious use of shadow-producing means.

The underlying concept and principles, and the several embodiments and modifications will now be particularized in tr e following discussion.

1 Detailed description of the invention My invention will be better understood from the drawings, particularly FIGURES 1 and 2. FIGURE 1 shows one embodiment om my lighting fixture it), this embodiment being of the pendant type, that is, suspended from the ceiling 12 by means such as hangers 14.

The structure of fixture lit is shown in the cross sec tional view of FIGURE 2. As may be seen, this com prises a lamp 16, preferably of the elongate fluorescent type, mounted in sockets such as 1%; suitable transformers, starters, current limiters, and the like being positioned at any convenient location.

My lighting fixture it} comprises the usual open, eggcrate-type bottom grill 2% that directs light downwardly and sidewardly to a limited extent. Bottom grill 20 has longitudinal slats 22, and transverse slats 24, these slats coacting to produce cells that extend through the grill 2%) from the inner face 25 to the outer face 26. These cells are preferably cubic, as this geometric formation prevents light from leaving grill 20 at an angle greater than degrees from the vertical, as shown diagrammatically by the shielding angle limit light rays 28. Rays 28 define a shielding boundary, the area below these rays being exposed to direct light from the fixture, and being known as the unshielded zone; whereas the area above rays 28 is shielded, and is therefore known as the shielded zone.

I contemplate the use of side panels 30 wherein the vertical slats 31 are transverse as shown in FIGURE 1, and the longitudinal slats 32 are angled, preferably at 45 degrees, as shown in FIGURE 2. This angled relation of the slats produces cells that are of rhombohedron shape and extend from the inner face 34 to the outer face 36 of the angled panels 30. By rhombohedron shape it is meant that the cells in the preferred embodiment have the geometric configuration of an oblique substantially square-based prism, that is, the cross section is a square, while the axis is oblique to the base.

It may thus be seen that when the angled panels 36 are positioned vertically, the cells thereof direct light upwardly toward the ceiling 12, from whence it is diffusely reflected to illuminate both the shielded and unshielded Zones. Angled side panels 30 may transmit as much as 95-98% of the lateral light, as compared with the transmission of some prior-art translucent side panels. Moreover, they permit free pass-age of air, which tends I to cool the lamp and prevent deposition of dust.

' in the shielded zone.

It will be noted that light traversing the angled panels 7 will pass through readily if it is directed either hori .and is eventually diffusely reflected from the ceiling into .the shielded zone.

The angled panels have another important advantage,

.namely they illuminate the ceiling so that there is less contrast between the brilliantly lighted fixture and the darker ceiling. This reduced contrast is also beneficial inavoidin g eye fatigue.

My fixture may be assembled in any convenient manner; one method being the use of thermoplastic adhesion techniques to afiix 'the various sections together in a utilized assembly. Alternatively, clips, screws, clamps, or other such devices may be used. The fixture may be \formed of any suitable material, plastic having the advantages that it may be readily molded, is lightweight, and has a transluscency and diffusive characteristics that soften the overall appearance.

FIGURE 3 shows a lighting fixture 37 of the same I general type and adapted to be surfiace-mounted directly against'the ceiling. Any suitable mounting clips, such as 38, as may be used; and if desired, a top plate 42 may be used. If desired, the lower surface 44 of top plate 42 may be made reflective to improve the overall efiiciency of the fixture.

panels 45 are thinner than those previously discussed,

although its cells are still oblique, square-based prisms. It Wil be seen from FIGURE 3 thatthe light rays 48 that define the shieldirlg boundary are now sloping tsliglitly downward. This result, achieved by a thinner angled panel whose angled slats are still at 45 degrees, directs less light toward the ceiling, and produces a some.- wvha-t smaller shielded zone.

This controlledthickuess feature permits the use of ,substantially the same angled :panel with its inherent advantages, and yet allows the illuminating engineer to select the shielding angle that is optimum for each placed at another angles by suitably adjusting the thickness of angle panels 52, 54. I

While the angle of 45 degrees is mentioned above and the cells cubic, this can be varied widely. One set of cell .walls in any panel can be disposed at any acute angle to the other set of cell walls in that panel, and the ihickness of the panel is correspondingly varied to provide the required shielding angle.

Of course, top plate 60 may have its lower surface 62 reflective to increase the efiiciency of the lighting fixture. a

The lighting fixture 64 of FIGURE 5 is similar. to that previously discussed, the dilference being that it accommodates two lamps 66 and 68 for more light. In order to provide the necessary space fixture 64 may have a bottom grill 79 similar to that of FIGURES l and 2.

The embodiments of FIGURES 1-5 preferably have end-plates, which may be transluscent, opaque, or per- ,forated. In order to take full advantage of my invention,

the end pieces may also comprise angle panels having rhombohedeon shaped cells. 1

The embodiments of FIGURES 2 and 3 when thus modified, appear as in'FiGURE 6, wherein the fixture 72 has the overall appearance of an open topped box;

the vertical ends and sides 74 of which direct light upward toward the ceiling, while the angled slats provide a shielding boundary at the desired-angle in all directions.

the shielding boundary may have a dillerent angle in the front-back and side-*to-side directions.

In rrounns. s and 7, the larrrp-holding socxets' 16 may be attached to a top plate, or'to suitably positioned ibrackets.

, It will be noted that the fixtures built in accordance with my invention have louvered sides and, if used, bottoms. This structure produces a sturdy, light-weight unitized low-cost fixture with lighbdirection control, and free passage for air. The various light-directing elements extend beyond the lamp in both directions in order to utilize the maximum amount of light emitted by the lamp.

The usefulness of my fixture may be improved even further, if the various slats have shadow-producing shoulders positioned as shown in FIGURE 8, that is, shoulders of generally triangular cross section extending horizontally from each side of each slat, the apices of all of the shoulders being in a single plane parallel to the corresponding inclined face of the panel. Light from the lamp 82 is intercepted by shoulders 8b, which therefore cast shadows indicated by the stippled areas 84. These shadows on the cell Wall cause the wall to appear dark, and thus further minimize the eye strain and tendency of the eye to turn toward the light.

It is preferable, in this case, for the shadow-producing shoulders to be positioned toward the bottom of the "cell wall.

Otherwise stated, the shoulders are in that portion of the panel remote from the light source in the fixture. This position of the shoulders places the shadows at the lower portion of the cell wallthat is seen by the viewer, and also tends to prevent the randomly scattered and reflected light from destroying the darkening efiect produced by the shadows.

Advantages It will be realized that my invention provides innumerable advantages over prior-art lighting fixtures. First, it is much more efficient due to the high light transmission of the angle panels as compared with the lower light transmission of translucent plates. Second, it is much lighter in'weight. Third, it permits the use of brighter lamps. Fourth, it'provides air flow that cools the lamps and minimizes the deposition of dust, Fifth, it provides an easily controlled boundary between the shielded and unshielded zones. Sixth, it controls light distribution in all directions; and finally, strategically produced shadows permit the sur face brightness to be reduced to more easily tolerated intensities.

It is understood that minor variation from the form of the invention disclosed herein may be made without departure from the spirit'and scope of the invention, and

that specification and drawing are to be considered as merely illustrative rather than limiting.

I claim:

l. A lighting fixture comprising:

a lamp; and

a pair of upwardly extending panels positioned relative to each other and disposed generally laterally of and on generally horizontally opposite sides of said lamp, said upwardly extending panels having an inner face,

an outer face, and a plurality of intersecting slats forming a cellular lattice of similar rectangular-based, light-directing rhombohedron cells extending through said panel obliquely relative to said faces and extending from one face to the other face, all of said cells being open ended, whereby accumulation of dirt and dust Within the fixture is prevented, said panels being unitized into a single panel assembly.

2. The combination of claim 1 wherein the slats form ing said cells have protruding shoulders generally triangular in cross section and parallel to the inclined outer surface of said panels that cast shadows on portions of said slats remote from said lamp.

3. An elongated lighting fixture comprising:

a lamp; 7

a pair of planar angle panels positioned parallel to each other and disposed generally laterally of and on generally horizontal opposite sides of said lamp; and

a pair of planar angle panels positioned parallel to each other and disposed at generally horizontally opposite ends of said lamp,

all of said angle panels having an inner face, an outer face and a plurality of intersecting slats forming a cellular lattice of similar rectangular-based, light directing rhombohedron cells extending through said panel obliquely relative to said faces and extending from one face to the other face, all of said cells being open ended, whereby accumulation of dirt and dust within the fixture is prevented, said panels being unitized into a single panel assembly.

4. The combination of claim 3 wherein said slats forming said cells have protruding shoulders adjacent said outer face, generally triangular in cross section and parallel to 10 the inclined outer surface of said panels, that cast shadows on portions of said slats remote from said lamp.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A LIGHTING FIXTURE COMPRISING: A LAMP; AND A PAIR OF UPWARDLY EXTENDING PANELS POSITIONED RELATIVE TO EACH OTHER AND DISPOSED GENERALLY LATERALLY OF AND ON GENERALLY HORIZONTALLY OPPOSITE SIDES OF SAID LAMP, SAID UPWARDLY EXTENDING PANELS HAVING AN INNER FACE, AN OUTER FACE, AND A PLURALITY OF INTERSECTING SLATS FORMING A CELLULAR LATTICE OF SIMILAR RECTANGULAR-BASED, LIGHT-DIRECTING RHOMBOHEDRON CELLS EXTENDING THROUGH SAID PANEL OBLIQUELY RELATIVE TO SAID FACES AND EXTENDING FROM ONE FACE TO THE OTHER FACE, ALL OF SAID CELLS BEING OPEN ENDED, WHEREBY ACCUMULATION OF DIRT AND DUST WITHIN THE FIXTURE IS PREVENTED, SAID PANELS BEING UNITIZED INTO A SINGLE PANEL ASSEMBLY. 